Intentional Stent Stenosis to Prevent Hyperperfusion Syndrome after Carotid Artery Stenting for Extremely High-Grade Stenosis

BACKGROUND AND PURPOSE:Intracranial hemorrhage due to hyperperfusion syndrome is a severe carotid artery stent placement complication of extremely high-grade stenosis, causing hemodynamic insufficiency. To prevent hyperperfusion syndrome, we attempted intentional residual stent stenosis and implemented “gentle” carotid artery stent placement, defined as carotid artery stent placement using a closed-cell stent coupled with slight balloon predilation, without balloon postdilation. Gradual stent expansion was expected. We investigated the incidence of hyperperfusion syndrome and long-term outcomes after gentle carotid artery stent placement.MATERIALS AND METHODS:We included patients who underwent carotid artery stent placement for extremely high-grade stenosis from January 2015 to March 2019. We defined extremely high-grade stenosis as carotid stenosis with conventional angiographic “slow flow” and a reduced MCA signal intensity on MRA. A reduced MCA signal intensity was defined as MCA with a relative signal intensity of <0.9 in the ipsilateral compared with the contralateral MCA. We evaluated the stent diameter, CBF on SPECT, hyperperfusion syndrome, and intracranial hemorrhage. We defined hyperperfusion syndrome as a triad of ipsilateral headache, seizure, and hemiparesis.RESULTS:Twenty-eight of the 191 patients met our inclusion criteria. After carotid artery stent placement, their median minimal stent diameter was 2.9 mm, which expanded to 3.9 mm at 4 months. Neither cerebral hyperperfusion syndrome nor intracranial hemorrhage occurred.CONCLUSIONS:The gentle carotid artery stent placement strategy for intentional residual stent stenosis may prevent hyperperfusion syndrome in high-risk patients. Stents spontaneously dilated in 4 months.

Hyperperfusion syndrome (HPS) is a critical complication of carotid revascularization.^1-4 HPS occurs after revascularization of extremely high-grade carotid artery stenosis (ex-HS) causing cerebral hemodynamic insufficiency.^1,5 SPECT was used in Japan to assess hemodynamic insufficiency before carotid artery stent placement (CAS) in 127 (82.5%) of 154 institutions;⁶ however, the risk of HPS was evaluated routinely by only 102 (15.5%) of 664 anesthesiologists in a US survey about carotid endarterectomy,⁷ and SPECT was not included in the survey. Thus, a simple index to identify high-risk patients is required. Classic angiographic “slow flow” in the MCA⁴ or reduced MCA signal intensity (SI) on MRA⁸ is a feasible index in most facilities. We, therefore, defined an ex-HS with a carotid artery stenosis rate of > 80% or a minimal luminal diameter (MLD) of <1 mm, coupled with angiographic slow flow and reduced SI in the ipsilateral MCA, as hemodynamic insufficiency (HI) criteria.The prevention of HPS has not been established,^9,10 though staged revascularization is a treatment option.^11,12 Therefore, we attempted to perform intentional residual stent stenosis to prevent marked hyperperfusion after CAS. To retain stent stenosis intentionally, we implemented “gentle” CAS, defined as CAS using a closed-cell stent coupled with slight balloon predilation, without poststenting balloon dilation. Compared with open-cell stents, the closed-cell stents may slowly self-expand and decrease embolic complications by avoiding dislodgement of the plaque while the stent expands, because the radial force in closed-cell stents is weaker than that in open-cell stents.¹³ Gradual and gentle self-expansion of the stent was the expected outcome.We investigated the incidences of hyperperfusion phenomenon (HPP), HPS, and intracranial hemorrhage (ICH) and the long-term clinical and angiographic outcomes after gentle CAS for ex-HS identified by the HI criteria.⁸ Furthermore, we evaluated the validity of the HI criteria.     

Time-of-Flight MR Angiography for Detection of Cerebral Hyperperfusion Syndrome after Superficial Temporal Artery–Middle Cerebral Artery Anastomosis in Moyamoya Disease

BACKGROUND AND PURPOSE:Cerebral hyperperfusion syndrome is a potential complication of superficial temporal artery–MCA anastomosis for Moyamoya disease. In this study, we evaluated whether TOF-MRA could assess cerebral hyperperfusion syndrome after superficial temporal artery–MCA anastomosis for this disease.MATERIALS AND METHODS:This retrospective study included patients with Moyamoya disease who underwent superficial temporal artery–MCA single anastomosis. TOF-MRA and SPECT were performed before and 1–6 days after anastomosis. Bilateral ROIs on the source image of TOF-MRA were manually placed directly on the parietal branch of the superficial temporal artery just after branching the frontal branch of the superficial temporal artery and on the contralateral superficial temporal artery on the same axial image, respectively. The change ratio of the maximum signal intensity of the superficial temporal artery on TOF-MRA was calculated by using the following formula: (Postoperative Ipsilateral/Postoperative Contralateral)/(Preoperative Ipsilateral/Preoperative Contralateral).RESULTS:Of 23 patients (26 sides) who underwent the operation, 5 sides showed cerebral hyperperfusion syndrome postoperatively. There was a significant difference in the change ratio of signal intensity on TOF-MRA observed between the cerebral hyperperfusion syndrome and non-cerebral hyperperfusion syndrome groups (cerebral hyperperfusion syndrome group: 1.88 ± 0.32; non-cerebral hyperperfusion syndrome group: 1.03 ± 0.20; P = .0009). The minimum ratio value for the cerebral hyperperfusion syndrome group was 1.63, and the maximum ratio value for the non-cerebral hyperperfusion syndrome group was 1.30. Thus, no overlap was observed between the 2 groups for the change ratio of signal intensity on TOF-MRA.CONCLUSIONS:Diagnosis of cerebral hyperperfusion syndrome is indicated by an increase in the change ratio of signal intensity on TOF-MRA by more than approximately 1.5 times the preoperative levels.

Moyamoya disease (MMD) is a chronic occlusive cerebrovascular disease characterized by bilateral steno-occlusive changes at the terminal portion of the internal carotid artery and an abnormal vascular network at the base of the brain.¹ Superficial temporal artery (STA)-MCA anastomosis is the standard surgical treatment for MMD. The incidence of cerebral hyperperfusion syndrome (CHPS) after STA-MCA anastomosis for MMD was reported to range from 15.0% to 38.2%.^2–5 With CHPS, transient focal neurologic deterioration is often exhibited, and if intracerebral hemorrhage occurs, it may lead to permanent neurologic deficits.⁶ Therefore, it is important to evaluate the regional cerebral blood flow after STA-MCA anastomosis for MMD.Positron-emission tomography and single-photon emission CT are criterion standard tools for the evaluation of regional CBF in patients with MMD^4,7–9; however, they are time-consuming modalities and require the injection of a radiotracer. MR imaging is a powerful method for comprehensive assessment of the brain without radiation exposure, and time-of-flight MR angiography is widely available. An increase in the signal intensity (SI) of the donor from the STA on TOF-MRA after STA-MCA anastomosis is observed in some patients with MMD.^2,3,6 Furthermore, we have previously reported that TOF-MRA revealed an increase in SI at the middle cerebral artery after carotid endarterectomy and that the SI changes corresponded to acute hemodynamic changes.¹⁰ In the present study, we used similar methods to retrospectively investigate whether CHPS diagnosis could be performed on the basis of the degree of increased SI in the donor from the parietal branch of the STA on TOF-MRA after STA-MCA anastomosis for MMD.     

Endovascular Treatment of the Carotid Stump Syndrome

In patients with an occluded internal carotid artery, the carotid stump syndrome is a potential source of microemboli that pass through the ipsilateral external carotid artery and the ophthalmic artery to the territory of the middle cerebral artery. Thus, the syndrome is associated with carotid territory symptoms although the internal carotid artery is occluded. Surgical exclusion of the internal carotid artery associated with endarterectomy of the external carotid artery has been described as the gold standard of treatment by many authors. This report is the second case, to our knowledge, of endovascular treatment of the carotid stump syndrome with the use of a stent-graft.     

Endovascular Management of Superior Mesenteric Artery Pseudoaneurysm and Fistula

The uncommon presentation of an arterioportal fistula (APF) involving the superior mesenteric artery (SMA) associated with a pseudoaneurysm represents a therapeutic challenge. We present the case of a 24-year-old female admitted to the hospital after multiple gunshot wounds to the abdomen; the patient underwent multiple surgeries and, in the process, developed a SMA pseudoaneurysm and fistula. The vascular interventional radiology team was consulted for treatment of the pseudoaneurysm and fistula. A covered stent was inserted percutaneously to exclude the APF and the pseudoaneurysm in a single procedure. The patient returned to our service after 21 months for a follow-up CT scan, which demonstrated the stent and the distal vasculature to be patent.     

Endovascular Treatment of Iatrogenic and Traumatic Carotid Artery Dissection

This paper reports on the early and midterm results of endovascular treatment of acute carotid artery dissections, its specific problems, and its limitations. We encountered seven patients with symptomatic extracranial carotid artery dissection, three cases of which occurred after carotid endarterectomy, two after carotid angioplasty and stenting, and two after trauma. Balloon-expandable and self-expanding stents were placed using a transfemoral approach. Success in restoring the carotid lumen was achieved in all patients. No procedure-related complications occurred. All patients experienced significant clinical improvement while in the hospital and achieved complete long-term recovery. At follow-up (mean, 22.4 months), good luminal patency of the stented segments was observed. In conclusion, in this small series, primary stent-supported angioplasty seems to be a safe and effective strategy in the treatment of selected patients having acute traumatic extracranial carotid artery dissection, with excellent early and midterm results. Larger series and longer-term follow-up are required before definitive recommendations can be made. Stefan Schulte and Konstantinos P. Donas contributed equally.     

Combined Endovascular Treatment with Distal Radial Artery Coil Embolization and Angioplasty in Steal Syndrome Associated with Forearm Dialysis Fistula

Purpose

The present study was performed to define the results of the endovascular treatment with angioplasty and distal radial artery embolization in ischemic steal syndrome associated with forearm arteriovenous accesses.

Method

The cases referred to our interventional radiology unit with symptoms and physical examination findings suggestive of ischemic steal syndrome were retrospectively evaluated first by Doppler ultrasonography, and then by angiography. Cases with proximal artery stenosis were applied angioplasty, and those with steal syndrome underwent coil embolization to distal radial artery.

Results

Of 589 patients who underwent endovascular intervention for dialysis arteriovenous fistulae (AVF)-associated problems, 6 (1.01 %) (5 female, 1 males; mean age 62 (range 41–78) with forearm fistula underwent combined endovascular treatment for steal syndrome. In addition to steal phenomenon, there were stenosis and/or occlusion in proximal radial and/or ulnar artery in 6 patients concurrently. Embolization of distal radial artery and angioplasty to proximal arterial stenoses were performed in all patients. Ischemic symptoms were eliminated in all patients and the AVF were in use at the time of study. In one patient, ischemic symptoms recurring 6 months later were alleviated by repeat angioplasty of ulnar artery.

Conclusion

In palmar arch steal syndrome affecting forearm fistulae, combined distal radial embolization and angioplasty is also an effective treatment method in the presence of proximal radial and ulnar arterial stenoses and occlusions.

     

Endovascular Treatment of a Coronary Artery Bypass Graft to Pulmonary Artery Fistula with Coil Embolization

Fistula formation between a coronary artery bypass graft (CABG)and the pulmonary arterial circulation represents a rare cause of recurrent angina in patients following bypass grafting. Therapy has traditionally involved surgical ligation by open thoracotomy. We describe a case of left internal mammary artery–left upper lobe pulmonary artery fistula presenting as early recurrent angina following CABG. The fistula was embolized using platinum coils, resulting in symptomatic relief and improvement in myocardial perfusion on cardiac perfusion scintigraphy. Coil embolization should be considered a therapeutic option in patients with coronary–pulmonary steal syndrome.     

Successful Endovascular Treatment of a Left Common Carotid Artery Aneurysm Following Failed Surgery of a Right Common Carotid Artery Aneurysm

Aneurysm of the common carotid artery is a rare and serious disease requiring prompt treatment in order to avoid neurologic complications. A 39-year-old man presented with voice impairment and a pulsatile mass at the right side of his neck and was found by color Doppler examination to have bilateral common carotid artery aneurysms of unknown origin. The right-sided large aneurysm was treated with placement of an 8 mm interposition Gore-Tex graft between the right common and internal carotid arteries. The surgical graft thrombosed 7 days after the surgery but the left-sided aneurysm was successfully treated by a Jostent peripheral stent-graft. Color Doppler examination showed a patent stent and no filling of the aneurysm on his first and sixth-month follow-up. Bilateral common carotid artery aneurysm is an exceptionally unusual condition and endovascular treatment of carotid artery aneurysms with covered stents may become an effective treatment alternative for these lesions.     

Symptomatic Internal Carotid Artery Dissecting Pseudoaneurysm: Endovascular Treatment by Stent-Graft

Dissecting pseudoaneurysm of the extracranial portion of the internal carotid artery (ICA) is a usually benign complication of spontaneous ICA dissection. We report a case in which pseudoaneurysm volume enlarged progressively and new clinical symptoms developed 9 months following disease onset. Placement of a coronary stent-graft resulted in immediate complete resolution of clinical symptoms and radiologic restoration of normal flow.     

Percutaneous Embolization of a High-Flow Pancreatic Transplant Arteriovenous Fistula

Percutaneous endovascular techniques were used to treat an arteriovenous fistula (AVF) associated with pancreatic transplantation. A pancreatic transplant superior mesenteric artery-to-superior mesenteric-vein AVF was successfully embolized while flow to the pancreas transplant was preserved. The embolization was aided by the use of Guglielmi detachable coils and a detachable balloon. No complications were encountered. At 23 months follow-up, the patient is doing well with no recurrence.     

颈动脉狭窄在脑保护装置下的支架置入治疗

目的探讨颈动脉狭窄患者支架治疗中的脑保护装置的有效性和安全性及治疗意义。方法对14例颈动脉狭窄患者进行血管内支架治疗。全部应用了脑保护装置(滤网型)。结果14例患者成功地释放了18枚自膨式支架。其中2例发生微栓子脱落轻度卒中,治疗1～3d完全恢复,颈动脉狭窄6例出现短暂性心率减慢和低血压。随访期所有患者均未发生脑梗死。结论在支架治疗中,脑保护装置的应用可减少治疗中的神经并发症,是一种有效和安全的治疗方法。     

Associations between Cerebral Embolism and Carotid Intraplaque Hemorrhage during Protected Carotid Artery Stenting

BACKGROUND AND PURPOSE:Carotid artery stent placement in patients with intraplaque hemorrhage remains controversial because of the incidence of cerebral embolism after the procedure. The purpose of this study is to determine if intraplaque hemorrhage is a significant risk factor for cerebral embolism during carotid artery stent placement.MATERIALS AND METHODS:This prospective study assessed 94 consecutive patients with severe carotid stenosis. These patients underwent preprocedural carotid MR imaging and postprocedural DWI after carotid artery stent placement. Intraplaque hemorrhage was defined as the presence of high signal intensity within the carotid plaque that was >200% of the signal from the adjacent muscle on MPRAGE. We then analyzed the incidence of postprocedural ipsilateral ischemic events on DWI and primary outcomes within 30 days of carotid artery stent placement.RESULTS:Forty-three patients (45.7%) had intraplaque hemorrhage on an MPRAGE image. There was no significant difference in the incidence of postprocedural ipsilateral ischemic events and primary outcomes between the intraplaque hemorrhage and non–intraplaque hemorrhage group. However, postprocedural ipsilateral ischemic events were more frequently observed in the symptomatic group (17/41 [41.5%]) than in the asymptomatic group (8/53 [15.1%]; P = .005).CONCLUSIONS:Intraplaque hemorrhage was not a significant risk factor for cerebral embolism during carotid artery stent placement in patients with severe carotid stenosis. Symptomatic patients should receive more careful treatment during carotid artery stent placement because of the higher risk of postprocedural ipsilateral ischemic events.

Extracranial carotid artery stenosis is considered a causative factor in 20%–30% of all strokes.^1–3 Large randomized clinical trials showed that carotid endarterectomy is superior to carotid artery stent placement (CAS) for the management of carotid artery stenosis.^4–6 Other randomized clinical trials showed that CAS and carotid endarterectomy offer similar efficacy.⁷ Although indications for CAS remain controversial, CAS has emerged as a less-invasive treatment that requires shorter hospital times than carotid endarterectomy.Some studies found a relationship between the baseline presence of carotid intraplaque hemorrhage (IPH) and the development of ischemic stroke in previously asymptomatic and symptomatic patients.^8–10 IPH is associated with plaque progression and, consequently, induces luminal narrowing. Thus, IPH may serve as a measure of risk for the development of future ischemic stroke. The risk of cerebral embolism after CAS in patients with IPH is controversial. Yoshimura et al¹¹ reported that a high-intensity signal on TOF MRA indicates that carotid plaques are at high risk for cerebral embolism during stent placement. However, Yoon et al¹² reported that protected CAS seems to be safe in patients with severe carotid stenosis and IPH. This study did not perform DWI to evaluate ipsilateral ischemic lesions. In addition, these studies used TOF imaging to detect IPH. Alternative techniques proposed for more accurate detection of IPH include heavily T1-weighted techniques, such as the MPRAGE sequence. Ota et al¹³ reported that the MPRAGE sequence demonstrated higher diagnostic capability in detecting IPH when compared with conventional T1-weighted sequences or TOF sequences.We prospectively designed the study with the following inclusion criteria: 1) preoperative multicontrast carotid plaque MR; 2) protected CAS; 3) postprocedural imaging, including DWI and noncontrast CT within 24 hours; and 4) clinical outcomes after 30 days. The aim of this study was to determine whether IPH is a significant risk factor for cerebral embolism during CAS.     

大脑后动脉动脉瘤的血管内治疗

目的 评价血管内方法治疗大脑后动脉动脉瘤的安全性和效果.方法 回顾性分析8例经血管内栓塞治疗的大脑后动脉动脉瘤的治疗效果、并发症以及随访情况.结果 8例患者均成功进行治疗,3例闭塞载瘤动脉,5例选择性栓塞动脉瘤,均无严重并发症.2例巨大动脉瘤患者闭塞载瘤动脉后头痛加重,2周后缓解.全部患者术后随访症状均消失,无动脉瘤破裂发生.结论 血管内方式治疗大脑后动脉动脉瘤,是安全有效的方法.     

血管内支架治疗颈动脉及椎动脉狭窄的20例临床分析

目的探讨血管内支架治疗颈动脉及椎动脉狭窄的安全性及有效性。资料与方法对20例颈、椎动脉狭窄行颈动脉球囊扩张及支架成形术(CAS)治疗的患者作回顾性分析,对临床表现、治疗方法及治疗前后的影像资料改变进行分析。结果 20例患者行CAS治疗,共成功放置支架22枚,11例采用颈动脉保护装置。术前干预血管平均狭窄度(76.2±11.4)%,术后支架膨胀不满意采用球囊后扩者3例。术后造影显示15例残余狭窄度<10%,4例<20%,仅1例<38%,术后平均狭窄度(12.4±8.2)%。治疗前后狭窄度比较有显著统计学意义(P<0.001)。随访平均(12.3±5.6)个月,7例支架术后6个月发现支架有不同程度再狭窄,但再狭窄率均未超过30%,均无神经系统症状。结论血管内支架治疗颈动脉及椎动脉狭窄是安全和有效的,近期随访无严重再狭窄(>50%)及颅内严重并发症发生。     

Endovascular Exclusion of an External Carotid Artery Pseudoaneurysm Using a Covered Stent

Aneurysmal lesions of the external carotid artery are extremely rare. A case is presented of a 3.8 cm right external carotid artery pseudoaneurysm treated by transluminal exclusion using an endovascular stent-graft. Following stent-graft placement, complete occlusion of the aneurysmal sac and main vessel lumen patency was successfully demonstrated. This report demonstrates the technical feasibility of utilizing stent-grafts to treat aneurysmal lesions involving the external carotid artery.